The present invention concerns a process for the recovery of carbon disulfide from a steam/carbon disulfide mixture which is produced, in particular, in the manufacture of viscose rayon when the wastewater from the yarn cutters and the suspension water are treated with steam.
The wastewater from the yarn cutters and the suspension water produced in the manufacture of viscose rayon are diverted into a trough where they are collected. In this collection trough, said waste water is treated with steam at temperatures of approximately 98.degree. C. The steam/CS.sub.2 mixture so generated is then drawn off.
It is known that carbon disulfide is recovered from the steam/CS.sub.2 mixture by using a heat-exchanging process to condense the steam, after which the carbon disulfide contained in the steam is obtained through subsequent cooling to the point of condensation.
In the prior art it is standard practice to draw in and convey the steam/CS.sub.2 mixture at a temperature of approx. 98.degree. C. using water or another suitable coolant in a parallel-flow configuration. This causes a portion of the steam to condense, while the remaining gas mixture is fed to a carbon disulfide condenser or an activated charcoal absorption system.
The coolant, which simultaneously acts as the means of conveyance, is warmed to temperatures of 50.degree. to 70.degree. C. by the high temperature of the steam/CS.sub.2 mixture. The temperature increase of the coolant depends on the pressure loss in the system, since the volume of coolant to be supplied varies as a function of the pressure loss.
One disadvantage of this process is that the mean is of conveyance is simultaneously the coolant. As a result, a very large quantity of liquid, which is heated by the steam/CS.sub.2 mixture to a temperature which depends on the pressure loss in the system, must subsequently be cooled down to the point of condensation. Cooling such a large quantity of liquid requires a great deal of energy. Another disadvantage of this known process is that relatively large quantities of liquid are required and must be moved.